Process of drying granular material



C. VV. CAHIER.

IJROCESS 0F DRYING GHANULAR MATERIAL. APPLICATION FILED APR.22, 1918.`RENEWED DEC. in

July I2, IIQZII.

54 @e (f4 62 5,52%56 i@ 4@ C. VV. CARTER.

PROCESS OE DHYING GRANULAR MATERIAL.

APPLICATION FILED APR. 22. 1918.

55 the time required CLRENCE W. CMTER, 0F MJTNIEAPLIS, TEIN'NESOTA.

PROCESS OF DRYEENG GRANULAR IWATERIAL.

i Application led April 22, 1918, Serial No. 229,910. )Renewed Decem ToaZZ whom t may concern: Y

Be it known that l, CLARENCE W. CARTER,

a citizen of the United States, residing at Minneapolis, in the countyof Hennepin and State of Minnesota, have invented certain new and usefulImprovements in Processes of Drying Granular Material, of which thefollowing is a specification.

My invention relates to a process of drying granular material and inparticular 'to a process of drying grain in which heated air is passedthrough a mass of grain having the form of a vertical column containedin large bins from the bottom of which the l5 grain is drawn off afterit has been dried.

ln processes of this kind in use before my invention the grain has beendrawn of slowly at the bottom of the bin and the temperature to which itis feasible to heat the air is limited, since if the temperaturegoesmuch beyond a certain degree the grain is seriously damaged by theheat. lt is wellknown that if material which is being heated isthoroughly stirred at su'iciently short intervals of time, it can be'subjected to a much greater degree of heat without injury than is thecase where it is not stirred or is only slightly stirred. Before thetime ofmy invention no satisfactory way of thoroughly stirring andagitating the grain had been devised, it not being practicable tointroduce mechanical stirrers or agitators into the bins, and since theslow passage of grain out of the bottom causes but slight miXin of themass, the temperature of the heate air has necessaril been restricted,as ypreviously stated. urthermore, it has previously been the custom todraw the grain through restricted openings at the bottom of the bins,

and this produces currents in the mass, some portions thereof movingdownwardly much faster than other portions. Therefore by the presentmanner of drying in bins, not only is an undue amountV of time consumedbut lthe grain is not uniformly dried. kThe object ofv my invention istherefore to overcome the above-mentioned defects in regard to drying,and ll accomplish this object by making a radical change in the process.ln short, ll

570 have devised a practical way of thoroughly stirring and agitatingthe mass at short intervals of time. ll am therefore able to emplo,zmuch higher temperatures than previous y employed and thereby greatlyshorten to thorougy dry the grain, and to also dry it much more umi-Speciication of Letters Fatent. Pattmltcedl July 12, 921.,

ber 27, 1920. -SEIal N0. 433,432.

formly than has been the case heretofore. ll do this by causing the massof grain to descend at intervals by a progressive showering action.which produces a complete re-distribution of the kernels of grain suchas is obtained by a stirring or agitating operation. In order toinitiate this redistributingeifect, l suddenly remove considerableportions of the mass from the bottom thereof and do this at intervalssuch that the time between successive removals of material isconsiderably longer than the time required for the removing operation.When the bottom portion of the mass is suddenly removed, a correspondingempty'space is left atL the bottom vof the bin and the mass is thereforesubstantially unsupported except for such support as it may have bybeing in contact with the numerous air ducts which extend through themass. 0n account of the frictional resistance odered by these air ducts,the mass when left unsupported at the bottom does not fall as a unit,butthe bottom portion thereof falls first, then a portion above the samefalls, and so on until the top of the mass is reached, thus producing ashowering action starting at the bottom of the unsupported' massand'running progressively up to the top thereof. .This showering orredlstributing eect is also aided by the fact that the grain isprogressively moister from bottom to top and the dried grain at thebottom does not tend to cohere as much as does the grain farther up inthe bin. l v

The full objects and advantages of my 1n` vention will appear inconnectlon withthe detailed description thereof and are particu-l larlypointed out in the claims. Y

Referring to the drawings, whlch illustrate a suitable apparatus forcarrymg outV my improved process,-

bin provided with means for carrying out my process. Fig. 2 is aI sideelevation thereof. Fig. 3 is a topl plan view of the operatlngmechanism. Figs. 4f, 5 and 6 are vlews 1n vertical section illustratingdi'erent positions assumed b the. grain which is being dried and discarged by the discharge pockets. j

lln the drawings 10 designates one of the customary drying bins whichare provided with upper conduits l2 for het air land lower conduits 1lifor cold air. rThe customary air' ducts extending across the bins aredesignated by the character V1 6, The hopper into gaa land 22 aresecured to i covers which the dried grain is discharged is designated bythe character l8. Two beams 2() opposite ends of the hopper 1.8 andthese beams are provided with journal 'bearings for a shaft 24. Se-

' .curedl to this shaft are three radial plates or \'to which aresecured a number of stepped outer end of'said arm is a pawl 54 which isvdriving pulleys 32 for changing the speed of operation of the device.Secured to the shaft 30 is apinion 34 in mesh with a gear 36 which issecured to a stub shaft 38 to which shaft is also secured a pinion 40 inmesh with a gear 42 loosely mounted on the shaft 24. It is evidentthat-a reduction gearing is thus provided between shaftf30 and the gear42. On one of the spokes of this gearis a projecting lug 44 for apurpose which will presently appear. On the end of the shaft 30 isa'crank arm 46 having a wrist pin 48 for operating a connecting rod 5()which is pivotally connected with an arm 52 loosely mounted on the shaft24. On the adapted at certain times to engage one of a l' series ofthree notches 56 provided` in the periphery of a disk 58 secured to theshaft 24. At other times this pawl slides idly back and 'forth .upon theperiphery of the disk. A bracket 60 carries a stop pawl 62 which isadapted to successively engage the notches 56 to prevent backwardmovement of the shaft 24. Secured to the shaft 24 is an arm 64 disposedin the path of the lug 44 previously referred to and adapted to beengaged at v imes by .said lug in the forward movement of the wheel 42.4It is evident lfrom this description 'that the' pockets have acomparativel long period of dwell under the bottom of tlie bin, and theystart to move with a slow turning movement which is soon converted intoa quick ,turning movement to discharge the grain. This quick turningmovement occurs as soon as the disk 58 has been turned sufficiently farto bring one of its notches within reach of the pawl: 54. The partialcover members 28 prevent escape lof the grain from the right-hand end,as will be evident from Figs. 4, 5 and 6.

The operation of the mechanism will be'A readily understood from theforegoing description. Upon applying the power toturn the shaft 30, thegear 42 will be rotated upon the shaft 24 at a greatly reduced speed.The

rotation of the gear 42 of course imparts rotation the shaft 24 onlywhen the lug 44 'comes in to engagement with the arm 64. When thisoccurs,- it is evident that the Shaft .juriously 24 and the dischargepockets will at first be turned slowly. The connecting rod 50 isoscillated by the crank arm 46 and causes the pawl 54 to oscillate idlyback and forth upon the periphery of the disk 58, except that when it isengaged with one of the notches. 56 it imparts a rapid turning movementto the disk 58 and tothe shaft 24, -carrying the discharge pockets. Itis evident from an inspection of Fig. 1 that .the pawl d'oes notoscillate sufficiently far to engage-.a notch in the position shown, andthat itis necessary for the lug 44 to catch up with the arm 58 andimpart a turning movement to the disk 58 until thepockets arrive atabout the unsupported at the bottom. The pockets then remain at restuntil the lug again catches up with the arm. It will thus be seen that apocket remains in the filling position shown in Fig. 4 .for anappreciable length of time and then moves slowly to about the positionshown in Fig. 6. The pocket is then moved very quickly to dischargingvposition and the next pocket brought into the lling position under thebin.' When the mass of grain is left unsupported at the bottom, thespace from which grain has just been removed is not instantaneouslyfilled, since vthe mass is partially supported by the baflie platespreviously referred to. A showering action results which is aided vbythe facts that the pressure at the bottom of this mass is greatest andthe grain is drier and has less c0- herence than the grain higher up inthe bin. The result is that the bottom portion of the mass falls firstin the forml of a shower, and a showering'action extends progressivelyup to the top of the mass of grain. This manner of descent causes tionvand mixing of the kernels of grain and prevents them from being actedupon inby the high degree of heat which is employed. The timing ofrotation of the pockets is such that each pocket remains at materialleft unsupported beneath the baffle a thorough redistribu- Fig. 4-4shows a pocket filled by the falling of the plates, while Fig. 5 showsthe showering action occurring farther upin the mass.

l claim:

l. A process of drying granular material which consists in supporting avertical column of said material at its bottom, passing heated airthrough said column, and periodically withdrawing said Support to anextent suficient to cause the entire column of material to move downwarduniformly throughout its cross section.

2. A process of drying granular material which consists in supporting avertical column of said material at its bottom, said column being of apredetermined length,

passing heated air through saio column throughout the principal part ofthe length thereof, periodically withdrawing said sup port to an extentsufficient to cause the entire column of material to move downwarduniformly throughout its cross section, and ,regulating the intervals oftime between each of said withdrawals so that the part of the materialwhich moves past the point of support and is discharged from the columnwill have been suitably dried.

ln testimony whereof l hereunto affix my signature.

CLARENCE w. CARTER.

